This proposal is for HIV Vaccine Preparedness studies with the following aims: 1) assess the feasibility of a vaccine efficacy trial in NYC. 2) to determine the seroincidence of HIV and its association with behavioral and biological cofactors; 3) to validate risk assessment scales to measure risk behavior associated with HIV transmission: 4) to evaluate the antigenic and genetic variability of HIV in the study population; 5) to contribute specimens for subsequent genetic and immunologic analysis.The lab was used for the following: DNA isolation, oligonucleotide synthsis, PCR, recombinant DNA techniques, RNA isolation, blood separation and use of laminar flow hoods.